CVE-2026-23309

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 5.5 from GitHub Security Advisory published 2026-03-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
5.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

tracing: Add NULL pointer check to trigger_data_free()

If trigger_data_alloc() fails and returns NULL, event_hist_trigger_parse() jumps to the out_free error path. While kfree() safely handles a NULL pointer, trigger_data_free() does not. This causes a NULL pointer dereference in trigger_data_free() when evaluating data->cmd_ops->set_filter.

Fix the problem by adding a NULL pointer check to trigger_data_free().

The problem was found by an experimental code review agent based on gemini-3.1-pro while reviewing backports into v6.18.y.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
25
EG Risk 25/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
1st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

March 25, 2026

Last Modified

June 17, 2026

Advisory Details (6)

Auto-updated Aug 6, 2026
Patch available.
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/59c15b9cc453b74beb9f04c6c398717e73612dc3
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/477469223b2b840f436ce204333de87cb17e5d93
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/457965c13f0837a289c9164b842d0860133f6274
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/42b380f97d65e76e7b310facd525f730272daf57
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2ce8ece5a78da67834db7728edc801889a64f643
Web page

tracing: Add NULL pointer check to trigger_data_free() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/13dcd9269e225e4c4ceabdaeebe2ce4661b54c6e

Vendor Advisories for CVE-2026-23309(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
linuxKernel @ 6.1.167 (fixes >=6.1.165)—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (121 versions)
  • every version up to 6.19.8-1: fixed in 6.19.8-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 31× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 207 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 108 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  2. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  3. 2026-10-18 03:54 UTCEG score recompute
  4. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  9. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  10. 2026-10-12 16:21 UTCEG score recompute
  11. 2026-10-11 20:03 UTCEG score recompute
  12. 2026-10-11 17:16 UTCEG score recompute
  13. 2026-10-11 14:48 UTCEG score recompute
  14. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  15. 2026-10-11 05:55 UTCOSV refresh
  16. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  17. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  18. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  19. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  21. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  22. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  23. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  24. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  25. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.1% · 1st percentile
Show 74 more
  1. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  2. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  3. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  4. 2026-09-24 14:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-09-21 17:49 UTCOSV refresh
  6. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  7. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  8. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  9. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  10. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  11. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  12. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  13. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  14. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  15. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  16. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  17. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  18. 2026-09-02 15:01 UTCOSV refresh
  19. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  20. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  21. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  22. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  23. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  24. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  25. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  26. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  27. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  28. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  29. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  30. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  31. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  32. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  33. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  34. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  35. 2026-08-16 10:23 UTCEG score recompute
  36. 2026-08-16 10:23 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  37. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  38. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  39. 2026-08-14 06:42 UTCEG score recompute
  40. 2026-08-14 06:42 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  41. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  42. 2026-08-13 00:11 UTCEG score recompute
  43. 2026-08-13 00:11 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  44. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  45. 2026-08-12 02:07 UTCEG score recompute
  46. 2026-08-12 02:07 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  47. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  48. 2026-08-11 04:03 UTCEG score recompute
  49. 2026-08-11 04:03 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  50. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  51. 2026-08-10 04:23 UTCEG score recompute
  52. 2026-08-10 04:23 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  53. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  54. 2026-08-09 06:15 UTCEG score recompute
  55. 2026-08-09 06:15 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  56. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  57. 2026-08-07 16:34 UTCEG score recompute
  58. 2026-08-07 16:34 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  59. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  60. 2026-08-06 01:03 UTCEG score recompute
  61. 2026-08-06 01:03 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  62. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  63. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  64. 2026-08-04 10:38 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  65. 2026-08-03 23:50 UTCEG score recompute
  66. 2026-08-03 23:50 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  67. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  68. 2026-08-02 15:37 UTCEG score recompute
  69. 2026-08-02 15:37 UTCGHSA enrichmentGHSA-f7v6-c4j6-g8wv · GitHub CVSS 5.5
  70. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  71. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  72. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  73. 2026-07-27 14:13 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  74. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.1% · 2nd percentile

Frequently asked(5)

What is CVE-2026-23309?
CVE-2026-23309 is a medium-severity vulnerability; its CVE record was published on March 25, 2026. In the Linux kernel, the following vulnerability has been resolved: tracing: Add NULL pointer check to triggerdatafree() If triggerdataalloc() fails and returns NULL, eventhisttrigger_parse() jumps to the out_free error path. While kfree() safely handles a NULL pointer, triggerdatafree() does not.…
When was the CVE record for CVE-2026-23309 published?
The CVE record for CVE-2026-23309 was published on March 25, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-23309 actively exploited?
CVE-2026-23309 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-23309?
CVE-2026-23309 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23309?
A fix for CVE-2026-23309 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-23309 are linked in the Vendor Advisories panel on this page.

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